Final answer:
The main difference between concurrent and retrospective coding is when the coding is done. Concurrent coding is done simultaneously with patient care, while retrospective coding is done after the patient has been discharged or the service has been provided.
Step-by-step explanation:
The main difference between concurrent and retrospective coding is when the coding is done. In concurrent coding, coding is done simultaneously with patient care, while in retrospective coding, coding is done after the patient has been discharged or the service has been provided. For example, in a hospital setting, concurrent coding would involve coding the patient's diagnosis and treatment while they are still in the hospital, whereas retrospective coding would involve coding the patient's medical records after they have been discharged.